A 59-year-old male patient presented with recurrent erythema and wheals all over the body for 6 years,complicated by irregular fever (the highest body temperature ＜ 39 ℃)and arthralgia for 2 months.He experienced a weight loss of 5 kg during two years prior to the presentation.Physical examination showed anemic comlexion,and there was no palpable enlargement of superficial lymph nodes,liver and spleen.Generalized erythema and wheals occurred all over the body,involving about 50％ of the body surface area.Histopathological examination of skin lesions showed infiltration of multiple neutrophilic granulocytes around blood vessels in the superficial dermis,and no vasculopathy was observed.Laboratory examinations revealed increased white blood cell (WBC) counts(13.97 × 109/L),erythrocyte sedimentation rate (ESR,136 mm/1 h) and C-reactive protein (CRP) level (75 mg/L),decreased hemoglobin level (96 g/L),and high serum levels of IgE (1 596 kU/L),IgG(20.4 g/L)and IgM(6 310 mg/L).Serum immunoelectrophoresis demonstrated that the IgM was a κ-type monoclonal immunoglobulin.Bone marrow examination showed active bone marrow hyperplasia.DNA sequencing analysis of 10 pairs of exons of the NLRP3 gene revealed 3 synonymous mutations,including c.663:C ＞ T:p.T221,c.732:G ＞ A:p.A244A and c.786:A ＞ G:p.R262R.Finally,the patient was diagnosed with Schnitzler's syndrome.There was no improvement of symptoms after the treatment with multiple oral antihistamines at increased dose levels.Then,the treatment protocol was adjusted to oral ciclosporin at a dosage of 200 mg/d for consecutive 18 days,but the patient still showed no response.After the treatment with oral prednisone (30 mg/d) and Tripterygium wilfordii tablets (66 μg thrice a day) for 2 weeks,the skin rashes subsided gradually,and arthralgia was relieved.Moreover,the WBC count,ESR and CRP level were decreased to 9.01 × 109/L,50 mm/1 h and 6 mg/L respectively,while the hemoglobin level was increased to 109.7 g/L.After 1-year follow-up,the dosage of glucocorticoids was gradually decreased to 8 mg/d.In addition,his condition was controlled well with no skin lesions and fever,except for occasional arthralgia in the knees and hip.